The present invention relates to a liquid crystal display device widespread in use as a display unit of various electronic equipment, and an electronic timepiece incorporating the liquid crystal display device as a display unit for displaying at least either of time information and calendar information.
A liquid crystal display device has thus far been widespread in use as a display unit of an electronic timepiece (watch, or clock), a cellular phone, a desktop electronic calculator, an electronic dictionary, a portable play station, and various other electronic equipment, for displaying information as required (in the form of characters and graphics).
With such a liquid crystal display device, it is useful to display three-dimensional information as required not only because of enhancement in deliverability of information so as to facilitate viewing of the information but also because of a greater possibility that a wider variety in design can be provided.
There has been available a conventional liquid crystal display device for displaying three-dimensional information, wherein a plurality of liquid crystal display panels are deposited on one after another such that three-dimensional display can be indicated by inputting different driving signals to the respective liquid crystal display panels.
However, such a conventional liquid crystal display device, as described becomes thick as it has the plurality of the liquid crystal display panels deposited on one after another, and is therefore unsuitable for use as a display unit of small-sized portable electronic equipment such as an electronic wrist watch which are under particular size constraints. Accordingly, it has not reached a stage of practical application.
The invention has been developed in view of such a situation as described above, and an object of the invention is to provide a flat type liquid crystal display device capable of three-dimensionally displaying characters and so forth without incorporating therein a plurality of liquid crystal display panels deposited on one after another, and also an electronic timepiece incorporating the liquid crystal display device, and capable of displaying time information and calendar information by use of the same.
In order to achieve the object described above, the invention provides a liquid crystal display device and an electronic timepiece that are made up as described in the following.
The liquid crystal display device according to the invention comprises a liquid crystal display panel and a reflector disposed on the side of the liquid crystal display panel, opposite from the visible side thereof. Further, the liquid crystal display panel comprises liquid crystal sandwiched between two transparent substrates, and display electrodes, made up of a transparent and electrically conductive film, provided on the inner faces of the respective substrates. The reflector is provided with protrusions formed at positions corresponding to the display electrodes, respectively, on a face thereof, opposite to the liquid crystal display panel.
With the liquid crystal display device according to the invention, made up as described above, when voltage is selectively applied to the display electrodes of the liquid crystal display panel for displaying information such as characters, and so forth, light transmitted through the liquid crystal display falls on the protrusions of the reflector. Not all components of light reflected from the surface of the protrusions reach a viewer at the same time but respective components of light will reach the eyes of the viewer with differences in arrival time due to the surface condition of the protrusions. As a result, display in the form of characters, and so forth, is three-dimensionally perceived by the viewer.
The liquid crystal of the liquid crystal display panel are preferably scattering type liquid crystal that undergo switching back and forth between a light scattering state and a transparent state by voltage applied from the display electrodes.
Since use of the scattering type liquid crystal can eliminate the need of using a polarizing film (sheet polarizer), it is possible to obtain a very high utilization efficiency of light, thereby enabling bright display to be effected.
In such a case, for the scattering type liquid crystal, any one selected from the group consisting of polymer network liquid crystal, polymer dispersion liquid crystal and dynamic scattering liquid crystal is preferably used.
Also, for the liquid crystal, guest-host liquid crystal provided with a dichroic dye may be used in place of the scattering type liquid crystal.
The plane pattern of the protrusions formed on the reflector is preferably rendered substantially in the form of a figure similar to that of the plane pattern of the display electrodes of the liquid crystal display panel. In such a case, the protrusions preferably has the pattern width narrower than that of the display electrodes of the liquid crystal display panel.
The protrusions of the reflector are preferably formed in a shape having a curved convex surface without ridgelines. Also, the protrusions of the reflector may be formed in a mushroom-like shape in section with the uppermost face having a curved convex surface and extending sideways from both sidewalls of the base of the respective protrusions.
The reflector is preferably made up of an aluminum sheet, and the protrusions are preferably formed of aluminum or material having a surface reflectance higher than that of aluminum, such as gold, silver, nickel, and so forth. Otherwise, the protrusions may be formed of copper, and a thin gold film may be formed on the surfaces thereof.
A surface reflectance of the uppermost face of the respective protrusions of the reflector may be differentiated from that of the side faces thereof. In such a case, the uppermost face of the respective protrusions is preferably rendered a mirror-finished surface while the side faces thereof are preferably rendered light scattering surfaces.
In the case where the respective substrates of the liquid crystal display panel are provided with a plurality of display electrodes for displaying different pieces of information, respectively, the reflector, is preferably provided with a plurality of protrusions at positions corresponding to the plurality of the display electrodes, respectively, formed on the face thereof, opposite to the liquid crystal display panel, and at least respective reflection faces of the plurality of the protrusions are preferably formed of materials in reflection colors differing from each other depending on spots of formation thereof.
In such a case, for the materials in different reflection colors, gold, silver or nickel, copper, and so forth, may be used.
A protective film of clear paint is preferably formed on the respective reflection faces of the plurality of the protrusions formed of such materials as described above.
Otherwise, the plurality of the protrusions may be formed of a coating of paints in different colors depending on spots of formation thereof on a reflection face of the reflector.
An electronic timepiece according to the invention is provided with a liquid crystal display device comprising a liquid crystal display panel for displaying at least either of time information and calendar information, and a reflector disposed on the side of the liquid crystal display panel, opposite from the visible side thereof. The liquid crystal display panel of the liquid crystal display device comprises liquid crystal sandwiched between two transparent substrates and display electrodes for displaying at least either of the time information and calendar information made up of a transparent and electrically conductive film formed on the inner face of the respective substrates. Further, the reflector is provided with protrusions formed at positions corresponding to the display electrodes, respectively, on a face thereof opposite to the liquid crystal display panel.
The configuration of the liquid crystal display device, and particularly, that of the reflector thereof can be variously modified as described in the foregoing.
The electronic timepiece according to the invention is capable of displaying time information and calendar information three-dimensionally, and consequently, its visibility can be improved and variety in design thereof can be increased.